export function HZRecorder(stream, config) {
    config = config || {};
    config.sampleBits = config.sampleBits || 16;   //采样数位 8, 16
    config.sampleRate = config.sampleRate || 16000;  //采样率16khz
   
    var context = new (window.webkitAudioContext || window.AudioContext)();
    var audioInput = context.createMediaStreamSource(stream);
    var createScript = context.createScriptProcessor || context.createJavaScriptNode;
    var recorder = createScript.apply(context, [4096, 1, 1]);
   
    var audioData = {
      size: 0     //录音文件长度
      , buffer: []   //录音缓存
      , inputSampleRate: context.sampleRate  //输入采样率
      , inputSampleBits: 16    //输入采样数位 8, 16
      , outputSampleRate: config.sampleRate  //输出采样率
      , oututSampleBits: config.sampleBits    //输出采样数位 8, 16
      , input: function (data) {
        this.buffer.push(new Float32Array(data));
        this.size += data.length;
      }
      , compress: function () { //合并压缩
        //合并
        var data = new Float32Array(this.size);
        var offset = 0;
        for (var i = 0; i < this.buffer.length; i++) {
          data.set(this.buffer[i], offset);
          offset += this.buffer[i].length;
        }
        //压缩
        var compression = parseInt(this.inputSampleRate / this.outputSampleRate);
        var length = data.length / compression;
        var result = new Float32Array(length);
        var index = 0, j = 0;
        while (index < length) {
          result[index] = data[j];
          j += compression;
          index++;
        }
        return result;
      }
      , encodeWAV: function () {
        var sampleRate = Math.min(this.inputSampleRate, this.outputSampleRate);
        var sampleBits = Math.min(this.inputSampleBits, this.oututSampleBits);
        var bytes = this.compress();
        var dataLength = bytes.length * (sampleBits / 8);
        var buffer = new ArrayBuffer(44 + dataLength);
        var data = new DataView(buffer);
   
        var channelCount = 1;//单声道
        var offset = 0;
   
        var writeString = function (str) {
          for (var i = 0; i < str.length; i++) {
            data.setUint8(offset + i, str.charCodeAt(i));
          }
        }
   
        // 资源交换文件标识符 
        writeString('RIFF'); offset += 4;
        // 下个地址开始到文件尾总字节数,即文件大小-8 
        data.setUint32(offset, 36 + dataLength, true); offset += 4;
        // WAV文件标志
        writeString('WAVE'); offset += 4;
        // 波形格式标志 
        writeString('fmt '); offset += 4;
        // 过滤字节,一般为 0x10 = 16 
        data.setUint32(offset, 16, true); offset += 4;
        // 格式类别 (PCM形式采样数据) 
        data.setUint16(offset, 1, true); offset += 2;
        // 通道数 
        data.setUint16(offset, channelCount, true); offset += 2;
        // 采样率,每秒样本数,表示每个通道的播放速度 
        data.setUint32(offset, sampleRate, true); offset += 4;
        // 波形数据传输率 (每秒平均字节数) 单声道×每秒数据位数×每样本数据位/8 
        data.setUint32(offset, channelCount * sampleRate * (sampleBits / 8), true); offset += 4;
        // 快数据调整数 采样一次占用字节数 单声道×每样本的数据位数/8 
        data.setUint16(offset, channelCount * (sampleBits / 8), true); offset += 2;
        // 每样本数据位数 
        data.setUint16(offset, sampleBits, true); offset += 2;
        // 数据标识符 
        writeString('data'); offset += 4;
        // 采样数据总数,即数据总大小-44 
        data.setUint32(offset, dataLength, true); offset += 4;
        // 写入采样数据 
        if (sampleBits === 8) {
          for (var i = 0; i < bytes.length; i++, offset++) {
            var s = Math.max(-1, Math.min(1, bytes[i]));
            var val = s < 0 ? s * 0x8000 : s * 0x7FFF;
            val = parseInt(255 / (65535 / (val + 32768)));
            data.setInt8(offset, val, true);
          }
        } else {
          for (var i = 0; i < bytes.length; i++, offset += 2) {
            var s = Math.max(-1, Math.min(1, bytes[i]));
            data.setInt16(offset, s < 0 ? s * 0x8000 : s * 0x7FFF, true);
          }
        }
   
        return new Blob([data], { type: 'audio/wav' });
      }
    };
    //开始录音
    this.start = function () {
      audioInput.connect(recorder);
      recorder.connect(context.destination);
    }
   
    //停止
    this.stop = function () {
      recorder.disconnect();
    }
   
    //获取音频文件
    this.getBlob = function () {
      this.stop();
      return audioData.encodeWAV();
    }
   
    //回放
    this.play = function (audio) {
     var blob=this.getBlob();
     // saveAs(blob, "F:/3.wav");
     audio.src = window.URL.createObjectURL(this.getBlob());
    }
   
    //上传
    this.upload = function () {
     return this.getBlob()
    }
   
    //音频采集
    recorder.onaudioprocess = function (e) {
      audioData.input(e.inputBuffer.getChannelData(0));
      //record(e.inputBuffer.getChannelData(0));
    }
   
  }